can be misleading as both zinc oxide and titanium dioxide are actually chemicals. Zinc oxide and to a lesser extent tita-
nium dioxide reflect a broad spectrum of UV wavelengths (both UVB and UVA) and are the only two filters that have been deemed GRASE in the recent FDA pro- posal. They are very stable, and as long as they sit on the skin surface they do the job. Chemical UV filters are a variety of
soluble organic compounds that absorb a range of UV wavelengths and convert it to heat. Most only filter a limited spectrum, therefore many different filters need to be mixed (or put together as a puzzle) into sunscreen to give a broad (UVB and UVA) coverage. Some chemical filters can be degraded by heat and have to be stabilised. The number of chemical filters is limited
Above: as a Star sailor of 40 years’ standing (and former world champion) Paul Cayard is also keeping at the front in the natty headgear stakes… Five-time Olympic medallist Torben Grael is another high-profile convert in the Stars, showing that coming from the hot Brazilian climate gives you no special privileges. Two good examples of top sailors making the unusual quite normal while encouraging others (left) to follow their example
dermatologist, to liquids, creams and sticks), sunscreens are categorised by their active ingredients which are the UV filters. In the US the FDA regulates sunscreens
as over-the-counter (OTC) drugs and requires that these ingredients be listed separately on the label under ‘active ingre- dients’. Some other countries, including countries in the European Union, however, do not have this requirement, so it is more
difficult to find them among all the other ingredients. In addition, a lot of the chemical filters
can carry several different names and are listed as such according to each country’s rules. The two main categories are insoluble, aka physical, mineral or inor- ganic filters, and the soluble, aka chemical or organic filters. Physical vs chemical, although the most frequently used terms,
in the US with only a few providing protection against UVA, including oxy- benzone, meradimate and avobenzone. In its recent regulatory proposal the FDA is planning to ask for additional safety data for all of the US chemical filters. Although permissible in the European Union, Aus- tralia and New Zealand, very broad-spec- trum chemical filters (Tinosorb M and Mexoryl XL) are prohibited by the FDA due in part to the lack of studies pertaining to absorption. Sunscreen manufacturers so far have
not conducted the FDA-required studies for the very broad-spectrum filters, but in my opinion the new environmental con- cerns regarding the existing US chemical filters may well prompt them to do so.
SEAHORSE 53
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